Remote Freelance Full Stack Developer Jobs in Denver, CO

Principal Java & .Net Software Engineer

Remote – US-Based Only

No visa sponsorship | No third-party agencies

** Must have Java and .Net experience **

We are seeking a Principal Software Engineer with deep technical expertise and a proven track record of defining architecture, guiding multiple teams, and delivering scalable, high-quality software systems. This role reports to the Director of Engineering and plays a critical leadership role in shaping the technical strategy and architecture across product lines, driving innovation, and enabling the development of both existing and next-generation platforms.

The ideal candidate will bring strong hands-on expertise in Java ecosystems, working knowledge of .NET technologies, and a technology-agnostic full-stack mindset. This individual will be experienced in cloud-native architectures, distributed systems, CI/CD, and modern AI-assisted engineering practices, with a passion for leading by example through active contribution to design and development, delivering end-to-end, innovative, high-quality solutions.

Duties and Responsibilities

• Define and evolve scalable, secure, and maintainable system architectures across one or more product lines, ensuring alignment with long-term platform strategy and business objectives.
• Drive end-to-end architecture across the full technology stack (UI, APIs, data, infrastructure), establishing standards for consistency, interoperability, and scalability.
• Establish and govern engineering best practices for design, development, testing, DevOps, and CI/CD pipelines to improve software quality and delivery velocity.
• Remain deeply hands-on by designing, building, and delivering complex system components, along with post-release support.
• Guide and influence multiple engineering teams on architecture, design patterns, and implementation approaches, ensuring alignment to enterprise standards.
• Make high-impact technical decisions including build vs. buy and platform selection, balancing trade-offs across performance, scalability, reliability, and cost.
• Design and drive adoption of cloud-native, microservices, and event-driven architectures for resilience and scale.
• Identify and mitigate cross-system dependencies, risks, and failure domains prior to large-scale releases.
• Champion AI-driven engineering practices including adoption of AI coding assistants and intelligent automation.
• Drive cross-functional alignment by partnering with Product, Design, Infrastructure, Security, Compliance, and Support teams to ensure cohesive architecture, seamless delivery, and adherence to operational and regulatory requirements.
• Analyze complex challenges and deliver broad-reaching, scalable solutions that improve system health.
• Define and monitor engineering metrics such as performance, reliability, and availability.
• Drive operational excellence through observability, monitoring, logging, and incident response frameworks.
• Mentor engineers and foster a culture of technical excellence, ownership, and continuous improvement.
• Influence stakeholders and drive alignment across teams to reduce complexity and enable effective decision-making.

Qualifications

• 12+ years of software engineering experience with architectural leadership.
• BS in Computer Science or related field.
• Strong expertise in Java (Spring ecosystem) and working knowledge of .NET.
• Experience with cloud platforms such as AWS, Azure, or GCP.
• Expertise in distributed systems, microservices, and API design.
• Experience with CI/CD, DevOps practices, and automation.
• Familiarity with front-end technologies such as Angular or React.
• Experience with relational and NoSQL databases.
• Exposure to AI/ML or AI-assisted software development tools preferred.
• Experience delivering large-scale, complex systems in Agile environments.
• Strong problem-solving, analytical, and communication skills.

Key Differentiators

• Background in invoicing, payments, healthcare, finance, supply chain, or similar domains.
• Experience working in global or distributed engineering environments supporting large-scale systems.
• Exposure to regulated domains and compliance standards such as SOC I/II, HIPAA, or GDPR.
• Ability to produce clear, structured, and technically accurate documentation.
• Ability to understand and explain the upstream/downstream systems and organizational impacts.
• Proven ability to challenge the status quo and drive continuous improvement.
• Strong leadership and mentoring skills, leading by example.
• Demonstrates emotional maturity and a positive, solution-oriented mindset.
• Strong analytical, prioritization, organizational, and time management skills.
• Lead by example by actively contributing to design and development, producing end-to-end, innovative, high-quality solutions.

Salary Range: $150,000 to $214,000 plus bonus